Pearson Edexcel International GCSE in Biology · 4BI1 · Free · no account needed
What Limits Photosynthesis — exam questions
9 original Incandio exam-style questions on what Limits Photosynthesis, 20 marks, about 20 minutes of writing. Each one carries the command word, the tariff and the specification statement it assesses, exactly as a paper presents them. This is an original Incandio practice question, written to reflect the structure and demands of the qualification. It is not an official Pearson Edexcel past-paper question.
This is the practice set for What Limits Photosynthesis — the lesson that teaches it. Read the lesson first if the idea is new; come here when you want to find out whether you can turn it into marks. Completely free, no account needed to read.
What these questions ask of you
8 command words run through this set, and on Pearson Edexcel International GCSE Biology each one means something precise. Answering the wrong command is the commonest way a candidate who understands the lesson still loses the mark.
- Which (1 mark)
- one option chosen from the set given
- State what is meant by (1–2 marks)
- the definition
- Name (1–2 marks)
- the correct term, spelled recognisably
- Describe (2–4 marks)
- developed, linked statements of WHAT happens — no reason required, but detail is Misread as: giving one bare statement where the tariff asked for a developed account
- Explain (2–4 marks)
- a causal chain — WHY it happens, each link a separate marking point Misread as: describing what happens without giving the reason it happens
- Calculate (1–3 marks)
- a numerical answer, with working where the tariff implies steps
- Give (1–2 marks)
- a short factual answer drawn from recall or from the data
- Suggest (1–3 marks)
- a plausible answer applying taught biology to a situation not taught
Assessed on Paper 1 (4BI1/1B) and Paper 2 (4BI1/2B), against AO1, AO2, AO3.
Where these sit in the specification
Pearson Edexcel International GCSE Biology (4BI1) — statements 2.23 · 2.20. Incandio is aligned to this specification; it is not published by, endorsed by or affiliated with Pearson, and it reproduces none of Pearson's wording.
The 9 questions
Answer them on paper, then open the lesson's exam practice to have them marked. The mark scheme, the accepted and rejected answers and the annotated model answer are in Incandio and are not printed here — an answer beside its question is not practice.
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Figure 1 — rate of photosynthesis against light intensity at 0.04% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 12 4 20 6 24 8 25 10 25 Figure 2 — the same experiment repeated at 0.14% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 16 4 30 6 40 8 46 10 47 (a)
(1)Give
Give the rate of photosynthesis in Figure 1 at a light intensity of 4 arbitrary units.
Figure 1 — rate of photosynthesis against light intensity at 0.04% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 12 4 20 6 24 8 25 10 25 Figure 2 — the same experiment repeated at 0.14% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 16 4 30 6 40 8 46 10 47 rate of photosynthesis = ............................ bubbles per minute
(b)
(3)Explain
Explain why the curve in Figure 1 levels off above a light intensity of 8 arbitrary units.
Figure 1 — rate of photosynthesis against light intensity at 0.04% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 12 4 20 6 24 8 25 10 25 Figure 2 — the same experiment repeated at 0.14% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 16 4 30 6 40 8 46 10 47 (c)
(2)Suggest
A grower whose glasshouse lamps already run at full power wants a bigger crop. Suggest what she should change, using both figures.
Figure 1 — rate of photosynthesis against light intensity at 0.04% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 12 4 20 6 24 8 25 10 25 Figure 2 — the same experiment repeated at 0.14% carbon dioxide, 20 °C. Plotted as a line; the graph is drawn in Incandio and the readings are below. Light intensity / arbitrary units Rate of photosynthesis / bubbles per minute 0 0 2 16 4 30 6 40 8 46 10 47 (Total for Question 1 = 6 marks)
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(1)Which
Which gas collects as bubbles when pondweed is illuminated under water?
Gas A carbon dioxide B hydrogen C nitrogen D oxygen (Total for Question 2 = 1 mark)
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(2)State what is meant by
State what is meant by a limiting factor.
(Total for Question 3 = 2 marks)
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(2)Name
Name the three factors that can limit the rate of photosynthesis.
(Total for Question 4 = 2 marks)
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(4)Describe
Describe how a student could investigate the effect of light intensity on the rate of photosynthesis in pondweed.
(Total for Question 5 = 4 marks)
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(2)Explain
Explain why the rate of photosynthesis in a field of wheat falls after sunset even though the temperature stays warm.
(Total for Question 6 = 2 marks)
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(3)Calculate
In one trial a student counted 51 bubbles in 3 minutes. In a second trial at a different distance she counted 84 bubbles in 4 minutes. Calculate how many times faster the second rate was than the first.
(Total for Question 7 = 3 marks)
Have them marked, then defend the answer
Practice tells you the mark; teaching it back tells you whether you understand it. On Incandio a topic counts as mastered only once you have taught it and defended it.
- Mark these questions — 9 questions, marked on Incandio against the authored scheme, with the mistake you actually made named.
- Teach it — explain what Limits Photosynthesis to Ember, an AI pupil who does not have it yet and asks the awkward question.
- Defend it — argue it against Jan Ingenhousz over three rounds, marked against descriptors you can read first.
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Back to the lesson
- What Limits Photosynthesis — Why brightening the light eventually stops working, how to read that off a graph, and the experiments that prove what a plant needs.
- All of Incandio Biology · Incandio Exam Practice